Apparatus for manufacture of filaments of varying denier

ABSTRACT

A FILAMENT-DRAWING APPARATUS FOR IMPARTING TO A THERMOPLASTIC FILAMENT A LENGTHWISE VARIATION OF DENIER, COMPRISING A FEED ROLL, A DRAW ROLL, A MATT CIRCUFERENTIAL BAND AND A MIRROR-FINISH CIRCUMFERENTIAL BAND ON THE CYLINDRICAL SURFACE OF THE DRAW ROLL, A SPEARATOR ROLL HAVING A MATT CLYINDRICAL SURFACE AND A FILAMENT DEFLECTOR FOR EXAMPLE A ROTARY CAM, ARRANGED TO DEFLECT INTERMITTENTLY THE FILAMENT FROM CONTACT WITH ONE BAND INTO CONTACT WITH THE OTHER BAND.

United States Patent Office Patented Feb. 9, 1971 3,561,045 APPARATUS FOR MANUFACTURE OF FILAMENTS OF VARYING DENIER Peter Helfernan, Carlisle, England, assignor to Courtaulds Limited, London, England, a British company Filed June 27, 1969, Ser. No. 837,045

Claims priority, application Great Britain, July 5, 1968,

32,128/ 68 Int. Cl. D01d /20 US. Cl. 18-1 4 Claims ABSTRACT OF THE DISCLOSURE A filament-drawing apparatus for imparting to a thermoplastic filament a lengthwise variation of denier, comprising a feed roll, a draw roll, a matt circumferential band and a mirror-finish circumferential band on the cylindrical surface of the draw roll, a separator roll having a matt cylindrical surface and a filament deflector, for example a rotary cam, arranged to deflect intermittently the filament from contact with one band into contact with the other band.

T his invention relates to the manufacture of a variable denier, thermoplastic filament, for example of nylon or polyester.

It has previously been proposed to manufacture a filament of varying denier in a drawing operation employing a draw roll having a surface with polished and matt longitudinally disposed strips and a co-operating matt surfaced separator roll. The process relies on the filament being engaged by the draw roll without slipping when the arc of contact lies largely on a polished strip or strips and slipping on the roller when the arc of contact lies largely on a matt strip or strips. We have found that this process does not provide the pronounced slubs or denier variations required in many fancy yarns.

According to the present invention a filament-drawing apparatus for imparting to a thermoplastic filament a lengthwise variation of denier, comprises a feed roll, a draw roll, a matt circumferential band and a mirrorfinish circumferential band on the cylindrical surface of the draw roll, a separator roll having a matt cylindrical surface and a filament deflector arranged to deflect intermittently the filament from contact with one band into contact 'with the other band.

The invention includes the process of imparting a lengthwise variation in denier to a thermoplastic filament by metering the undrawn filament, passing the filament in less than 2 turns about a separator roll and a draw roll, the separator roll having a matt cylindrical surface and the draw roll having a matt circumferential band and a mirror-finish circumferential band on its cylindrical surface, and intermittently deflecting the filament from contact with one band into contact with the other.

An embodiment of the invention is illustrated in the accompanying schematic drawing, in which FIG. 1 is an elevation of a station on a draw-twister, and

FIG. 2 is a profile of a cam.

Referring to FIG. 1, an unstretched multifilament yarn passes by way of a cott roller 2 and a feed roll 3 to be wound in one turn about a draw roll 4 and a separator roll 5 and thence through a guide 6 and a ring-spinning collection device 7 onto a package 8. The separator roll 5 is spaced from the draw roll 4 and has its axis of rotation slightly inclined to the axis of the draw roll.

The cylindrical surface of the draw roll 4 is divided into two contiguous circumferential bands, one band 9 is matt and the other 10 is polished to a mirror-finish.

The separator roll 5 has a matt cylindrical surface. Between the feed roll 3 and the draw roll 4, a cam 11 is mounted on a driven shaft 12, alongside the yarn 1. The cam 11 has a profile incorporating a smalled diameter are 13 and a larger diameter are 14. As shown in FIG. 1, when the smaller diameter are 13 of the cam profile is in contact with the yarn 1 it does not deflect the yarn 1 from its natural straight path between the feed roll 3 and the polished band 10 on the draw roll 4. However, when the cam 11 is rotated so that the yarn 1 is in contact With the larger diameter are 14, the yarn is deflected to the yarn path 1A shown in broken line. The deflection causes the yarn wrapped on the draw roll 4 and separator roll 5 to move from the polished band 10 to the matt band 9. As the cam 11 completes a revolution, so that once again the yarn 1 is in contact with the smaller diameter are 13, the yarn 1 reverts under its own tension to the undeflected path and the wrap on the draw roll 4 and separator roll 5 moves back onto the polished band 10.

When the yarn wrap is located on the polished band 10 there is little if any slippage between the yarn and the band so that the yarn is drawn to the full extent dictated by the ratio of the peripheral speeds of the draw roll 4 and feed roll 3. When the wrap runs on the matt band 9, however, the wrap skids on the band and is not drawn to the theoretical extent. The yarn collected on the package 8, therefore has alternating drawn and less drawn lengths, which endow the yarn with a lengthwise variation of deniers.

A difference in the grip of the bands 9 and 10 on the yarn was always found when the visual appearance of the bands was matt and polished respectively. However, a further definition of roughness of a band was needed to distinguish degrees of difference in the performance of various paired bands. A commercially available device was employed to characterise the surfaces of the bands one in which a sensitive finger traversed a line in contact with the surface registering the spacing of the micropeaks thereon. The polished band 10 had closely spaced micropeaks and the matt surface more separated micropeaks. It is preferred that the polished surface should have a roughness, i.e. an average spacing of peaks of at most 0.2 micron and better still at most 0.15 micron, whilst the matt surface preferably should have a roughness of at least 1 micron, say in the range of 1.25 to 1.4 micron.

The dwell time of the yarn wraped on the draw roll 4 and the separator roll 5, on the bands 9 and 10 is determined by the angles a and B subtended by the larger and smaller diameter arcs 14 and 13 respectively, and the speed of revolution of the cam 11, which may be varied to randomise the length and spacing of thicker parts of the drawn yarn.

The apparatus was employed to stretch a yarn of sixteen polycaproamide filaments with a ratio of the peripheral speeds of the draw roll 4 and the feed roll 3 of 3.12:1. The yarn was wrapped 1 /2 times on the roll 2 and once on the draw roll 4 and separator roll 5. The peripheral speed of the draw roll was 730 metres/minute and the spindle speed of the collection device 7,500 revolutions per minute.

The undeflected path of the yarn 1 from the feed roll 3 to the draw roll 4, located the warp on the polished band at a distance of 3 mms. from the boundary with the matt band 9. The cam 11 was located so that the smaller diameter arc 13 1.9 cms. radius, 3=90) touched the yarn path 1 without deflecting it. The larger diameter arc 14 had a radius of 3.5 ems. and a subtended angle, a, of

The cam 11 was rotated at 626 revolutions per minute for Series A and at 376 revolutions per minute for Series B. The analysis of the yarns made in both series is presented in the following table.

band and a mirror-finish circumferential band contiguous therewith on the cylindrical surface of the draw roll, a

Peak denier to peak What is claimed is:

1. A filament-drawing apparatus for imparting to thermoplastic filament a lengthwise variation of denier, comprising a feed roll, a draw roll, a matt circumferential band and a mirror-finish circumferential band on the cylindrical surface of the draw roll, a separator roll having a matt cylindrical surface and a filament deflector arranged to deflect intermittently the filament from contact with one band into contact with the other band.

2. A filament drawing apparatus as claimed in claim 1 in which the filament deflector is a cam and driving means to rotate the cam.

3. A filament drawing apparatus as claimed in claim 2 in which the matt circumferential band has a roughness of at least 1 micron and the mirror-finish circumferential band has a roughness of at most 0.2 micron.

4. A filament-drawing apparatus for imparting a lengthwise variation of denier to a thermoplastic filament, comprising a feed roll, a draw roll, a matt circumferential separator roll having a matt cylindrical surface, a cam and driving means therefor, arranged to deflect the filament laterally from contact with one band into contact with the other band and to allow the filaments to revert,

1 at least once in each cam cycle.

References Cited UNITED STATES PATENTS 0 2,038,722 4/1936 Dreyfus et al. 264167 3,416,188 12/1968 Fukuma et a1. 264290 3,422,491 1/1969 Kihara et a1 264167 JULIUS FROME, Primary Examiner 25 H. MINTZ, Assistant Examiner US. 01. X.R. 

